These clinical studies are based on data collected in Africa and Thailand. There is a correlation between HIV viral load (blood levels) and HIV transmission. Specifically, the higher the viral load in the blood, the more likely the chance for transmission. Antiretroviral therapy (ART) reduces the viral load in the blood, as well as in genital secretions (for both men and women), and the drugs can be detected in semen and vaginal and cervical secretions. This information strongly suggests that ART may reduce the risk that HIV-infected people will transmit HIV. HPTN 052 compares the HIV-infection rates of two groups of HIV-serodiscordant couples.